Diez,
What does the function._marked accomplish?
Diez B. Roggisch wrote:
> WakeBdr schrieb:
> > I'm writing a class that will query a database for some data and return
> > the result to the caller. I need to be able to return the result of
> > the query in several different ways: list, xml, dictionary, etc. I was
> > wondering if I can use decorators to accomplish this.
> >
> > For instance, I have the following method
> >
> > def getUsers(self, params):
> > return users.query(dbc)
> >
> > To get the appropriate return types, I also have these methods. I have
> > these convenience methods for every query method in my class.
> >
> > def getUsersAsXML(self, params):
> > return self._toXML(self.getUsers(params))
> > def getUsersAsDict(self, params):
> > return self._toDict(self.getUsers(params))
> > def getUsersAsList(self, params):
> > return self._toList(self.getUsers(params))
> >
> > Instead of creating these three methods for every query method, is
> > there a way to use decorators to manipulate the return type. I'd still
> > like to have the caller use getUsersAsXML, I just don't want to write
> > the AsXML methods for every query method. So the decorator would
> > essentially create the convenience methods instead of me coding them.
> >
> > One solution that I don't want to use is passing a variable into the
> > query method that determines the return type. This is what I don't
> > want to do.
> > def getUsers(self, params, returnType):
> >
> > Any ideas on how I can accomplish this?
>
> Use a metaclass.
>
> class Magic(type):
> def __new__(cls, name, bases, d):
> for name, function in d.items():
> try:
> function._marked
> def toXML(self, *args, **kwargs):
> return self._toXML(function(self, *args, **kwargs))
> def toFOO(self, *args, **kwargs):
> return self._toFOO(function(self, *args, **kwargs))
> d[name + "XML"] = toXML
> d[name + "FOO"] = toFOO
> except AttributeError:
> pass
> return type(name, bases, d)
>
>
> def mark(f):
> f._marked = True
> return f
>
> class MyClass(object):
> __metaclass__ = Magic
>
> def _toXML(self, value):
> return "Look Ma, its XML! %r" % value
>
> def _toFOO(self, value):
> return "Look Ma, its FOO! %r" % value
>
>
> @mark
> def someMethod(self):
> return "Its the data, son"
>
>
> o = MyClass()
>
> print o.someMethod()
> print o.someMethodXML()
> print o.someMethodFOO()
>
>
>
> Diez
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